U.S. Pat. Nos. 4,591,870 and 4,623,897 describe a continuous ink jet printer intended for use in an office environment. To meet the requirements of such an environment, the printer is relatively small and employs a miniature print head that traverses a print platen to print successive line portions of a print sheet on the platen. The office environment also dictates that the printer be easy to "start-up", be substantially free from any complicated user maintenance and not require frequent service calls. To provide this capability, the printer includes a built-in start-up and maintenance station, commonly called a home station, which is located at the side of the print head traverse path. The print head is moved over, and into sealed relation with, a chamber of the home station where various cleaning, drying and diagnostic operations are performed under control of programs stored in the printer's control system.
For example, the above cited U.S. patents describe how: (i) ink and ultrasonic vibrations are used to clean the orifices and the droplet charging and catcher surfaces of the print head; (ii) ink solvent condensate is used to wash those surfaces; and (iii) pressurized air is directed to skive and dry those surfaces. Excess ink flows from the home station back to the main ink reservoir of the printer. U.S. Pat. No. 4,616,234 describes how an electrometer located in the home station can be used to measure the current produced by charged ink drops during testing sequences, effected by the printer control, to properly set the charging and stimulation pulses for the print head. These systems enable the miniature print head to provide high resolution output, reliably, in the intended office environment.
For certain applications it would be desirable to enable a miniature print head, such as described above, to have the capability to be located away from the printer mainframe for remote operation, with only umbilical connections for ink circulation and electronic control. This goal can be attained except for the problems of implementing start-up and periodic maintenance at a remote location, i.e. without the mainframe home station.